Comparative analysis of responses of minimum frequency of ionogram reflections and mesosphere-lower thermosphere temperature to winter sudden stratospheric warmings

The paper is devoted to the comparative analysis of the responses of the minimum frequency of reflections on ionograms (fmin) and the mesosphere-low thermosphere (MLT) temperature to the sudden stratospheric warmings (SSWs) in 2008, 2009, and 2013. The experimental basis for the research is the fmin measurements with the DPS-4 digital ionosonde in Irkutsk, the Aura/MLS satellite data on the atmospheric temperature at different altitudes, and the data on the rotational temperature of the hydroxyl molecule obtained from spectrometric measurements at ~100 km from Irkutsk. Comparative analysis of the behavior of fmin and the MLT temperature has revealed both a case of high correlation (SSW 2008) and no correlation (SSW 2009), along with an intermediate variant during the SSW 2013. The paper discusses the reasons for the different correlations between the analyzed parameters.